This invention relates generally as indicated to a flap wheel and more particularly to a fixed flap wheel which is inexpensive to manufacture, yet easy to operate, which can be recycled environmentally, and yet flexible in width, diameter, or flap type refills.
Most flap wheels with insertable flap segments or bundles use flaps secured to the hub with hinges or with a flexible rubber or plastic holder to act as though hinged. This permits the flaps to bend over to an open position as the tool rotates and as the flaps encounter the part. The flaps then curve away from the direction of rotation but tend to spring back from the open position as they clear the part due to centrifugal force. This is in part why they are called flap wheels. The flaps tend to flap about and create excessive noise and wear, the latter due primarily to flap-to-flap wear caused by relative movement of flap against flap.
Also, such hinged flap wheels rely on the arcuate bending of the bundles of flaps to expose the outer edge of the face of the flap to the work. Although the flaps in any bundle are normally the same length, a flap extending around the outside of a curve will have an edge termination before one extending around the inside of the curve, since the distance around the inside is always shorter. For each wheel revolution there is a significant rubbing of flap against flap as the bundles move from the open or bent condition back to the radial position and then back to the open position all within one revolution of the wheel. A hinged flap wheel can literally wear itself out.
The hinge construction adds considerably to the cost of the tool or wheel and limits the recyclability of the tool. It also limits the simplicity of the tool, making it more difficult to change length, diameter, or to change the make-up of the flap bundle.
Accordingly, it would be desirable to have a simple fixed flap wheel where the outer edges of each flap face are exposed to the work without the constant flexing and rubbing. It would also be desirable to have a versatile flap wheel with few simple parts all made of aluminum so they can readily be recycled through aluminum recycle systems.
A flap wheel includes an anodized aluminum hub with outwardly opening peripheral slots. Flap clips also made of aluminum each holding a bundle of flaps fit snugly in the slots. The slots and clips include an elongated socket and knob construction. The socket of the slot and knob of the clip both have an arched or radius bottom and straight parallel side walls terminating in opposed retaining keys projecting inwardly from the side walls of the slot, or corresponding key ways in the clip. The outer ends of the clips include a thin wall U-shape flap bundle retention slot having a flat but skew or slanting bottom wall. The slots extend uniformaly in a non-radial direction angled away from the direction of rotation. The flat but skewed bottom of the clips also slants inwardly toward the direction of rotation to position or splay the outer edges of the flaps in the same skewed slanting direction exposing at the outer edge portion, each of the faces or flat surfaces of the flaps to the work as the wheel rotates. The flap bundles may be held in the clips by fasteners or staples extending through the thin walls and the inner ends of the flaps. The entire wheel may be refilled quickly, is lightweight and may be recycled. The flap arrangement provides additional cut, less flap-to-flap wear, and less noise. The diameter, arbor hole size, and axial length may vary. The hubs may be ganged or stacked to vary the lengths or face width of the wheel. The content of each flap bundle may vary widely, such as any combination of sizal, cloth, abrasive paper, abrasive belt material, or non-woven abrasive and the like.